<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <script src="http://g.tbcdn.cn/mtb/lib-flexible/0.3.4/??flexible_css.js,flexible.js"></script>
    <title>Document</title>
    <style>
        .test {
            width: 1.333333rem;
            height: 2.666667rem;
            background: black;
        }
    </style>
</head>

<body>
    <div class="test"></div>
</body>

</html>